(a) Field of the Invention
This invention relates to insecticidal compositions containing phototoxically effective ingredients and to the method of use thereof.
(b) Information Disclosure Statement
The use of sodium salts of various xanthene dyes as insecticides is well known. Such dyes owe their insecticidal effect to a photodynamic action of visible light on adult insects of their larvae that have ingested the dyes, for example from aqueous solutions thereof. A suggested mechanism for the toxic effect requires that the dye, in a ground singlet state, first absorbs a photon of visible light and thus becomes excited to a higher singlet energy state. Of several different possible paths the excited dye molecule can then take, in one path, it can transfer its excess energy to another molecule, such as an oxygen molecule, to form a highly reactive and toxic singlet oxygen. The toxic effect exerted by the thus energized oxygen is then manifested by tissue damage in the insects or larvae of such nature as to cause death of the organisms. [Heitz and Wilson, Photodegradation of Halogenated Xanthene Dyes, ACS Symposium Series, No. 73, Disposal and Decontamination of Pesticides, 1978]. This mechanism requires that the molecule be phosphorescent, and the greater the phosphorescence of the dye, the greater its photodynamic toxicity should be.
This mechanism also requires, of course, that the dye be ingested by the adult insects or their larvae, and in virtually all approaches to date to the use of xanthene dyes as photodynamic insecticides, water soluble forms, for example the sodium or potassium salts, are dissolved either in water, for example to test the efficacy of the dyes against mosquito larvae, or in sugar solutions, for example to serve as feed bait in studies against fire ants.
Thus Barbieri, Rivista di Malariologie, AO VII, 456-463 (1928) tested a variety of fluorescent materials for phototoxicity and found that rose bengal in combination with erythrosin as a "sensitizer" was particularly effective against Anopheles spp. Also found to be effective were erythrosin/esculin and erythrosin/eosin combinations, while an acridine/esculin combination was ineffective. Rose bengal alone, at dilutions from 1:10,000 to 1:2,000,000, was also effective, but esculin, acridine, sulfonal and Magdala Red (phloxin B) alone were all found to be ineffective.
Schildmacher, Biol. Zentr., 69, 468-477 (1950) examined a series of fluorescent dyes (uranin A, erythrosin J, eosin H.8.G., rose bengal, phloxin B., rhodamine B, acridine red and tryptaflavin) for their photodynamic toxicity to Anopheles maculipennis (second and third instars), Anopheles superpictas and Aedes aegypti mosquito larvae. Rose bengal and acridine red were found to be the most effective in all experiments at dilutions up to 1:100,000, and erythrosin and phloxin B were also found to be effective. Uranin, erythrosin and rhodamine were found to be ineffective.
Pimprikar, Norment and Heitz, Environmental Entomology, 8 (5), 855-859 (1979) studied the photodynamic toxicity of rose bengal against the mosquito larvae, Culex pipiens quinquefasciatus and Aedes triseratus, and found it to be an effective insecticide.
Yoho, Butler and Weaver, J. Econ. Ent., 64, 972-973 (1971) studied the photodynamic toxic effect of rhodamine, rose bengal, erythrosin B, eosin blue, phenosafranin, methylene blue chloride and uranine against house flies. Rhodamine, rose bengal and erythrosin B were found to be quite effective, and eosin blue moderately so. Phenosafranin, methylene blue chloride and uranine were found to be largely ineffective.
Pimprikar, Fondren and Heitz, Environmental Entomology, 9 (1), 53-58 (1980), tested erythrosin B against house fly larvae, Musca domestica, in chicken manure and found it to be an effective insecticide.
Fondren and Heitz, Environmental Entomology, 7 (6), 843-846 (1978) found rose bengal, erythrosin B, phloxin B, eosin Y and tetrachlorofluorescein to be photodynamically toxic in varying degrees against face flies, Musca autumnalis. Fluorescein, however, produced no toxic response.
Broome, Callaham and Heitz, Environmental Entomology, 4 (6), 883-886 (1975) found phloxin B and rose bengal to be effective insecticides against black imported fire ants, Solenopsis richteri, whereas erythrosin, eosin Y and rhodamine B were found to be ineffective.
David and Heitz, Agricultural and Food Chemistry, 26 (1), 99-101 (1978) describe the use of phloxin B free acid (D and C Red 27) in bait for fire ants, Solenopsis richteri and Solenopsis invicta. The bait consisted of corn cob grits, soybean oil and phloxin B free acid. The latter form of the dye was used, because it is soluble in the soybean oil, whereas the sodium salt (D and C Red 28) is not. The bait toxicity was found to be light dependent as well as light independent. The light dependent action is effective in hours, while the light independent action is effective in days.
Crounse and Heitz, U.S. Pat. No. 4,320,140 disclose synergistic insecticidal compositions containing at least one insecticidally active water-soluble xanthene dye selected from erythrosin and rose bengal in admixture with the essentially non-insecticidally active and synergistically-effective fluorescein sodium.